


Secret Night Detention

by ajisaihime



Category: IDOLiSH7 (Video Game)
Genre: Anal Fingering, Anal Sex, Explicit Sexual Content, Hand Jobs, Hands Free Orgasm, Kissing, Light Bondage, M/M, low-key roleplay
Language: English
Status: Completed
Published: 2019-07-08
Updated: 2019-07-08
Packaged: 2020-06-09 14:23:01
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,882
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/19477720
Author URL: https://archiveofourown.org/users/ajisaihime/pseuds/ajisaihime
Summary: A lost bet was a lost bet and Tenn was a man of honor.





	Secret Night Detention

**Author's Note:**

  * For [mattieleaf](https://archiveofourown.org/users/mattieleaf/gifts), [Frostychi](https://archiveofourown.org/users/Frostychi/gifts).



> We came up with this idea and I just had to write it down. I blame that one particular WacchaxSouma BLCD for providing the kinky Sensei part and I'll never be able to look at the Trigger academy cards the same innocent way again, thanks Bini, thanks Dani.

  
“It's my win. Now let me hear you say it.”

Gaku smirked and Tenn wanted nothing more but wipe it from his face. Every fiber of his being rejected the sentence he was pushing up his throat.

  
“Sensei,”, he gritted his teeth, “you won.”  
  


A lost bet was a lost bet and Tenn was a man of honor.  
  


When the script for their school drama with Idolish7 had been delivered, the Trigger members read it together as always. Tenn had mocked Gaku about his character, namely Keyboard Gaku, and had taunted whether he was able to portray the role if he didn't even know how to play a piano.

Their ensuing hotheaded bickering was ended by Ryuu who suggested to ask for piano lessons to settle things peacefully instead of fighting. Gaku turned this idea into a bet and proposed that he'd be able to play a moderately difficult piano piece in five days time.

  
Since it wasn't required for the acting job Tenn couldn't care less if Gaku was really able to manage but seeing him work his ass off was definitely something Tenn'd enjoy.

Only when Gaku claimed Tenn to call him S _ensei_ for the remaining time of their work on the series if he won, his confident smile faltered.  
  
Tenn was not that humble and requested for Gaku to buy him fifty donuts whenever he felt like having one if the bet went in his favor.

  
To Tenn's misfortune, Gaku was determined and fully motivated to give him a taste of defeat in time in one of Yaotome Production's rehearsal rooms after everyone else had left.

“Hah, that's even better than I imagined.”, Gaku chuckled and left his spot in front of the grand piano to stand up and pushed the prop glasses up his nose bridge.  
  
  
Tenn casually leaned on the instrument, elbows propped on the closed cover.  
  
“So there's more to you than your pretty face, I'm shocked you actually pulled it off. _Secret Night_ was a nice choice, though.”

  
“Watch it, Tenn.”  
  


“Or what? You gonna put me into detention?”, Tenn scoffed, referencing to his punishment and rolled his eyes.

  
Gaku suddenly closed in on him and trapped Tenn between his body and the piano.

“Maybe that's what I'll do if you continue to be so cocky, brat.”  
  


“My, my. You know,”, Tenn said playfully and brought his fingers to his lips to feign innocent indignation, “this is sexual harassment, S _ensei_.”

  
The on-point acting and the snarky emphasis on the last word was enough to make something inside Gaku snap. His hands cupped Tenn's face rather ruggedly and he pulled him in to crash their lips together.  
  
For once, Trigger's cheeky center was dumbstruck and frozen stiff, eyes open wide in surprise at the turn of events.  
  


It took Tenn a second or two to process what was happening. He finally reacted by pushing at Gaku's chest and emitting sounds of protest, given that his mouth was sealed shut by the others' lips.

Gaku released Tenn's rose colored face, who used his chance to give him an earful.

  
“What the hell do you think you're doing?!”, Tenn growled and let out a yelp when he felt Gaku's hands on his body, his waist and ass respectively.  
  
  
“I'm not listening if you don't address me properly.”, Gaku replied alluringly, his hands exploring leisurely – touching, rubbing, groping.  
  
  
“Gaku!”, Tenn objected again but he almost bit his tongue when Gaku squeezed them flush against each other and his lips brushed the sensitive skin of his neck, nuzzling that one particular spot right beneath his ear where his hairline was located.  
  
Tenn unintentionally shivered from the pleasure of it and Gaku's slender fingers pushing past the hem of his shirt where they glided along his bare spine.  
  
“Nh!”  
  


Both of them paused. Gaku retreated a bit to give Tenn, who apparently produced that sweet noise, a surprised look. Tenn was obviously irked and covered his mouth with the back of his hand, eyes firmly avoiding Gaku.

“So, that's your kink?”, Tenn uttered, an undeniable blush on his face, “Outrageous.”  
  


What had started as a joke turned into something serious, Tenn's rather honest reaction urged Gaku on to continue this game.

As there was no answer, Tenn brought himself to glance at him but Gaku kept staring in silence, a mischievous smile on his lips. His eyebrows twitched expectantly, overthrowing Tenn's patience and he swallowed his pride once more.  
  
“Sensei.”  
  
  
“Good boy.”, Gaku chuckled and reveled in the sight of Tenn's sullen expression as he squeezed his ass, “Judging your face, this seems to cater to your tastes more than mine.”  
  
  
“Don't treat me like a kid. And I beg to differ.”

A frown distorted Tenn's flushed pretty face but Gaku noticed that the pressure of Tenn's hands on his chest, the force that had tried to push him away, gradually weakened.

  
“We'll see about that.”

  
Crap, Tenn really wasn't aware how much he tempted Gaku, desire burning hot in his guts he decided to see how far he could take this before Tenn either slapped him across the face or ran off. If things came down to it, it was probably both plus a knee crushing his balls.  
  
  
But neither happened, on the contrary, Tenn didn't resist at all when Gaku kissed him again. It was presumably due to the growing bulge in his pants the Gaku was rubbing his palm against.

Honestly, Gaku didn't think he would get _that_ far as he unbuckled Tenn's belt and freed him from the clothing of his lower body, hand enclosing his dick to jerk him off slowly.

  
Tenn squeezed his eyes shut and pressed his mouth into a thin line. This situation was humiliating enough as it was and he was unwilling to reward Gaku with the last shred of his pride by moaning.

“Stubborn as always, huh?”, Gaku whispered and gave Tenn's trembling lips a sensual lick.

  
The question ignited a spark in Tenn and his fighting spirit returned.

“You wanna bet on my resolve?”, he smiled, brimming with self-confidence.  
  
  
“Yeah, let's do that.”, Gaku replied with a smirk and dropped to his knees.  
  
  
Not only did this procure a better angle to pleasure Tenn with, he was also able to attack his inner thigh and trail kisses along, gently biting down on the pale softness at times.

  
Feeling it was more than enough, Tenn couldn't stand to watch Gaku for very long so he used one hand to claw at the piano while he hid his face behind the other.  
  
He was embarrassed but also pretty turned on and given the positions they were in, he wouldn't be able to hide that fact like he could with his face.

  
Gaku noticed the shift of his limbs and glanced up at Tenn, stopping all activity.

“Hushing yourself is cheating.”  
  


Tenn reciprocated the look through his fingers. “I'd never."  
  


“You better not.”, Gaku said and and swiped his hand from Tenn's stomach to his chest, brushing his shirt along until Tenn's chest was bare. He brushed his thumb over Tenn's nipple, making him flinch.  
  
  
“Gaku..”

It sounded strained and desperate, but Gaku stayed relentless.  
  


“Honorific.”, he simply grunted and watched Tenn struggle with the wording of his subsequent sentence.  
  
  
“Sensei,”, Tenn gasped, “..you're slacking off.”  
  


His skin turned an even darker shade of red but his lips wore the ghost of a derisive smile and Gaku just gawked at him.  
  
He knew Tenn well enough to see through his spite and decipher the message behind it – that two-faced brat asked for a performance upgrade.  
If he weren't already uncomfortable in the tightness of his pants, he would've been by then.  
  


“Tenn, you're doing really great, I'll give you that.”, Gaku chuckled in a heated voice, “But I'm sorry. I gotta raise the bar.”  
  
  
Tenn inhaled sharply and held his breath as Gaku squeezed the base of his dick and pressed a kiss to his glans. And just when he had opened his mouth to take him in completely, Tenn practically shoved at Gaku's forehead.

“Is your resolve that weak?”, he asked disgruntled and established eye contact with Tenn.  
  


Tenn furrowed his brows, a dangerous gleam of defiance in his eyes that basically said _I'm not gonna lose to you again, idiot_.  
  
  
“Good.”, Gaku smiled and even more so when he saw Tenn's Adam's apple bob with a visible gulp.  
  


“No good.", Tenn mumbled, his hand remaining on Gaku's head, "It's been a long day and I didn't shower yet..”

  
Gaku's annoyed glare melted immediately. “I don't mind.”

  
“Well, _I do_.”

  
Gaku considered for a moment then pulled back. “All right.”  
  
  
Instead of sucking Tenn off he resumed the pumping hand motion on his erected dick, vexingly slow and gentle and fondled his chest with the other.  
  
Gaku had to admit he enjoyed this way too much and the small jerks of Tenn's hips which he tried to contain were a clear sign he did, too.  
For what it was worth, Gaku was absolutely positive he'd be able to make a mess out of Tenn that evening, seeing how hard he bit his lip and scrunched his face to hold back the forbidden moans of pleasure.

  
The fight of theirs was quite extraordinary this time but in no way aggravating, each of them finding themselves thinking they could get used to this. Both of them were in a deep competitive mode and Gaku didn't take his eyes off of Tenn for a single second, searching his impassioned features for a sign of a particular weakness whenever he changed something about the way of his touch.

  
Stroking the head of his cock with his fingertip seemed to be the most effective and Gaku could see Tenn's tenacity fade away – but he didn't budge completely, his self-control strong as ever. Tenn didn't allow himself the smallest sigh or moan although he was trembling like mad, fingers lost in Gaku's silver hair.

Gaku got impatient with him and let go of him completely. Tenn's following glare was amusingly reproachful when he snapped his eyes downward to look at him.

“Fuck it.”, Gaku breathed and stood up, “I wanna hear your voice.”  
  


“I'm not giving in.”, Tenn replied and closed his eyes halfway as Gaku kissed the corner of his mouth and dropped more of them along his cheek.  
  
  
A small whimper escaped him when Gaku licked the shell of his ear.

“I acknowledge your resolve, it's your win.”, Gaku whispered and his lips curled into a smile again as he felt Tenn shudder.  
  
  
After a moment of deliberation went by Tenn tilted his head and his forehead met with Gaku's shoulder.

“Fine. Keep going.”  
  


“You're being rude again.”, Gaku scolded him teasingly and nibbled Tenn's jawline.

  
“...Sensei, keep going.”

Gaku felt his skin prickling into goosebumps upon noticing the longing tone of Tenn's voice. He liked the usual and confident hedgehog Tenn the best but obedient Tenn was also quite charming.

"If you don't want me to stop again, you gotta undress me in my stead.", Gaku whispered, their noses almost touching at this point.

  
Tenn immediately loosened his necktie and discarded it on the piano cover. He started to unbutton his shirt when Gaku rubbed at the underside of his cock and that did the trick.

  
Tenn finally moaned wholeheartedly and it sounded like an angel's sigh to Gaku's ears. The visuals that came with it served as an accelerant, enlargened the flame burning behind his belly button and made him catch Tenn's mouth with his own.

Chaste lip touching melted into a passionate deep kiss with no haste involved at all until Tenn quietly moaned again against his lips. He finished opening up Gaku's shirt and continued with his belt and pants.

Messy sweet kisses shared in between, it was Gaku's turn to groan softly as soon as his hard-on was relieved from his pants but still restrained by his boxers.

  
Tenn's hand returned to Gaku's now bare pecs, this time it wasn't to push him away but to slide his fingertips across and down to his abs in a snake-like motion, selectively applying more or less pressure.

It was a simple touch, really, though it was so electrifying Gaku almost couldn't handle it. If Tenn continued this, he might've turned into a ruthless beast but this was supposed to be a fun game for both of them.

“New rule, hands off.”, he declared and turned Tenn around, “Yours, that is.”

Gaku removed the remaining clothes from Tenn's body and pressed against him to force him to place his torso onto the piano cover.  
  
  
“Oi, Sensei,”, Tenn complained and folded his arms, “why only me?”  
  
  
“Well, you're in detention, remember?”

  
Gaku grabbed the forgotten necktie and used it to tie Tenn's forearms up. Tenn allowed it, though he was a bit irritated by the progression that fitted way too conveniently into their role play.

He was also not pleased about the way his dick was uncomfortably squeezed to the piano and shifted backwards in need of more freedom until his ass met with Gaku's hands.

  
Tenn took a look over his shoulder to find that Gaku had stripped completely, except for his shirt and the fake glasses.

“You're really into this, aren't you?”, Tenn remarked sarcastically and closed his eyes when Gaku leaned on him, skin on skin, nuzzling his hair.  
  


“No, but I'm into _you_.”, Gaku breathed and made Tenn blush intensely, both by the answer and the sensation of Gaku's cock rubbing at his butt cheeks.

  
Gaku felt Tenn tense up briefly underneath him and snickered before he dropped a kiss on his neck. He was eager to tease Tenn even more now that he was so compliant and soft in his grip, cute even.

“I got nothing on me to make things slippery so we have two choices now.”, he said and brought a hand up to Tenn's chin, “Option A, I use my mouth.”  
  
  
Tenn shuddered at the thought and his dick twitched. “No way.”  
  
  
“Thought so.”  
  
  
“Option B?”  
  
  
“You provide some lube.”, Gaku replied and shrugged, gently caressing Tenn's chin and throat.

It was a little hard coming up with a solution for Tenn, but he wasn't called smart for nothing.

“I have Vaseline in my bag, though I usually use it for skincare.”  
  


A smile crossed his lips and it grew even wider when he heard Gaku click his tongue. Tenn was overly satisfied with himself and listened to Gaku fetch the desired item, carelessly flinging it to the floor shortly after he spooned out a good amount with his fingers.

  
Tenn's eyes were set on the necktie around his arms while Gaku coated his cock with the improvised lube first then rubbed his index and middle fingers against his thumb before he slipped them between Tenn's thighs.

He was anticipating the touch but flinched nonetheless, clenching his fists when a single digit entered him. Gaku proceeded to finger him thoroughly, twisted his hand slowly and experimentally scraped the walls that surrounded it. He added a second one to the game soon after which resulted in Tenn groaning softly.

  
It was little too late to spare a thought on this but Gaku was genuinely surprised. Tenn was cooler with all this and definitely wasn't as tight as he had supposed. He could only imagine the reason and that was a pretty hot one to picture.

Biting his lip, Gaku put a hand on Tenn's side and brushed it over his hipbone to get a hold of his cock, jerking him off again while he thrust a total of three fingers knuckle deep into his body.  
  


That, Tenn commented with louder noises of pleasure, his legs spreading apart on their own accord as Gaku matched the rhythm of his hands.

“Ah, Sensei!”

  
Gaku was so captivated by Tenn's unintentional responses and searching for his sweet spot, the call literally ripped him out of his daze.

He replaced his fingers with his cock, decisively grinding into Tenn causing his shoulder blades to shift closer together as he flexed his back and arched his upper body away from the instrument he lay on.

Since Gaku regrettably wasn't able to see Tenn's face while doing so, he watched his own dick being hungrily sucked in all the way until he was fully sheathed.  
  
He stayed perfectly still while Tenn consecutively clenched and relaxed his pelvic floor, nails scratching at the piano cover, trying to get used to the intruder.

“Shit, that feels amazing.”, Gaku sighed, trembling slightly.  
  


“Go on.”, Tenn hoarsely replied and nodded.  
  


As soon as Tenn gave his permission Gaku tightened the grip on his hips and made him meet his easygoing thrusts.  
  
Tenn went tingly all over and his breathing was uneven – but he was annoyed by Gaku's irregularity, teasing him with a few sped-up movements before he returned to the steady, calm pace.

It was all too shallow and gentle, he wanted – no, he desperately needed – Gaku to go deeper and faster than that.

“You're going too slow.”, he groaned, bordering on being whiny, and cursed the piece of fabric that restrained his arms.  
  


“Say that again.”, Gaku demanded, arousal evident in his voice and propped on one hand next to Tenn's shaking figure.

  
“Sensei.. _hurry_!”  
  
  
Tenn's voice cracked at the second word, slipping into a higher pitch, all embarrassment forgotten and replaced by pure desire.

Gaku had never heard Tenn being this vocally needy before, it made him tremble with excitement and quickened his already racing pulse significantly. One corner of his mouth turned upwards, moans of pleasure bubbling in his throat as he gave Tenn what he wanted and slammed into him repeatedly.

  
Each thrust was accompanied by Tenn's blatant almost-screams and he literally felt what a mess he was making on the side of the piano and the ground beneath him, his unattended dick heavily leaking precum.

The room got drastically hotter for both of them and Tenn rested his forehead on his arms, the glossy surface of the piano fogging up due to his open-mouthed breathing.  
  
Tenn had no time to swallow thus he additionally drooled on it, but he couldn't care less about soiling the production company's property at that moment.  
  
He didn't care about the possibility of getting caught by a staff member nor the fact he was complaining about before, that is to say that he didn't shower. He was sweaty and dirty by then anyway and the things Gaku did to him outweighed everything else.  
  


Tenn shuddered when Gaku kissed his back and fleetingly licked his spine.

  
“Tenn.. I'm..”  
  


He instantly raised his head, alarmed. “If you come inside of me.. I'm gonna kill you.”

  
“Spoilsport.”, Gaku pouted, “You go first, then.”

  
“Try to make an effort, then.”, Tenn sneered and turned his head to spite Gaku with an arrogant expression.  
  
  
The remark carried the same little devil energy as Tenn's comment that had started this all.  
  
  
Gaku gritted his teeth. “You damn brat.. you're really asking for it today, aren't you.”

  
“Oh no, Sensei, I wouldn't- nh!”  
  


He didn't let Tenn form another coherent word as he took him more aggressively and even harsher, firmly holding his hips and moving Tenn's body to slap against his.  
  
Gaku attempted to make Tenn climax by solely stimulating his sweet spot and he was utterly delighted to see it work out, enjoying the sight of Tenn trembling harder and his moans became even sweeter and more fervent.  
  
Tenn's legs were frantically shaking, friction and constant explosions of pleasure blew any other thought away. He wanted to touch himself _so badly_ to intensify the opacity of the stars he was seeing behind his eyelids but there was no need for that. Gaku handled him perfectly right as if he had known where to touch and kiss to unravel him from the very beginning.  
  
  
Eventually, Tenn was overwhelmed and banged his tied arms onto the piano a few times before he clenched up and came with Gaku's name on his lips.  
  
He kept whimpering afterwards because Gaku didn't slow down at all, granted him no time to compose himself in the least.

  
Now that Tenn had fallen almost silent he could hear Gaku's strained breathing, his passionate moans and he matched their panting to resound in unison.  
  
  
Gaku's rhythm suddenly stuttered and he cursed as he pulled his cock out of Tenn and briefly jerked himself to orgasm, coming all over the small of his back.

  
They both panted intensely, Gaku's left hand still on Tenn's hip and he couldn't resist the urge to spank his ass lightly.  
  
Tenn winced and gasped. He meant to get up from the instrument and reprimand Gaku but was held down against it.

  
“Stay put. I'm gonna get a tissue.”

A blush crept onto Tenn's face and he did what he was told until Gaku had cleaned his back carefully.  
  
  
Only when he finally returned to a standing position, facing Gaku, he noticed that he was similarly red around his cheeks and ears.

Gaku proceeded to free Tenn's arms and swiped another tissue from the box he had put on the ground prior to that action. He offered it to Tenn without directly looking at him, eyes fixated on the piano. Tenn thanked him quietly and rid his mouth and chin of his spilled saliva.

  
“I would've done that by myself.”, he mumbled as he watched Gaku wipe away the remains of his orgasm and sweat.  
  


“Nah, it's fine.”, Gaku simply replied and crumpled used tissue after used tissue to dispose of them afterwards.

  
The atmosphere was a little awkward when they got dressed, neither of them sure what to make of this or how to deal with the consequences, something they hadn't considered in their lust-filled minds.

“Tenn.”, Gaku addressed him after they were ready to leave, “Are your, uh, arms okay?”  
  


Tenn gave him a wide-eyed stare that turned into a smile. “ _Now_ you're worrying?”  
  


“I am.”  
  


After all, he had the feeling that he _did_ turn into a beast of some sort at last and was worried whether he had been too abrasive.  
  
Gaku paralyzed him by gently touching the side of his face and Tenn fumbled with his words.  
  
  
“Yeah.. I'm fine.”  
  


Gaku sighed relieved and leaned in to place a kiss on Tenn's cheek, “Would you pass me my necktie?”

  
Dumbfounded at first, Tenn absentmindedly picked up the red item they had misused for their hot and heavy time and automatically put it around Gaku's collar to tie it for him.

  
“By the way, is this yours or part of the costume?”  
  


“The costume but I might keep it after the shooting is complete.”

  
“Huh?”, Tenn inquired and they finally locked gazes.

  
“Well,”, Gaku smirked and got a hold of the others' hand, “maybe I need it again sometime, who knows?”

  
Without another word Tenn's fist greeted Gaku's stomach, punching the air out of him with a single blow. Gaku doubled over and groaned with pain while Tenn swiftly left the room, his heart beating twice as fast and he swore to himself that he would never ever engage in a bet with Gaku again.

  
The future use of the red necktie on the other hand was a different matter though.  
  


**Author's Note:**

> I'm not completely satisfied with this and it took longer than expected. Bini (you sweetheart!) had an absolutely gorgeous fanart made so I had to re-write a large part of the fic to include the necktie bonds.  
> Song is "Secret Night" by TRIGGER, what else.
> 
> Anyway, hope you enjoyed Gaku banging Tenn on a grand piano and thank you for reading this mess orz


End file.
